Gas distribution system, reactor including the system, and methods of using the same

ABSTRACT

A gas distribution system, a reactor system including the gas distribution system, and method of using the gas distribution system and reactor system are disclosed. The gas distribution system can be used in gas-phase reactor systems to independently fine tune gas source locations and gas flow rates of reactants to a reaction chamber of the reactor systems.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 14/218,690, filed Mar. 18, 2014, the disclosure of which is herein incorporated by reference in its entirety.

FIELD OF DISCLOSURE

The present disclosure generally relates to gas-phase reactors and systems. More particularly, the disclosure relates to gas distribution systems for gas-phase reactors, to reactor systems including a gas distribution system, and to methods of using the gas distribution systems and reactor systems.

BACKGROUND OF THE DISCLOSURE

Gas-phase reactors, such as chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD), and the like can be used for a variety of applications, including depositing and etching materials on a substrate surface. For example, gas-phase reactors can be used to deposit and/or etch layers on a substrate to form semiconductor device, flat panel display devices, photovoltaic devices, microelectromechanical systems (MEMS), and the like.

A typical gas-phase reactor system includes a reactor including a reaction chamber, one or more precursor gas sources fluidly coupled to the reaction chamber, one or more carrier or purge gas sources fluidly coupled to the reaction chamber, a gas distribution system to deliver gasses (e.g., the precursor gas(ses) and/or carrier or purge gas(ses)) to a surface of a substrate, and an exhaust source fluidly coupled to the reaction chamber. The system also typically includes a susceptor to hold a substrate in place during processing. The susceptor can be configured to move up and down to receive a substrate and/or can rotate during substrate processing.

Generally, it is desirable to have uniform film properties (e.g., film thickness and resistivity) across a surface of a substrate. Various gas distribution systems have been developed to attempt to achieve uniform or substantially uniform film properties. For example, gas distribution systems including multiple ports (e.g., up to 5) or nozzles located within the reaction chamber have been developed to increase uniformity of film properties across a substrate surface. However, such systems do not adequately address uniformity of film properties, particularly at or near an edge of a substrate. Additionally, such systems generally do not allow for independent control of film properties, such as film thickness uniformity and resistivity.

As sizes of features formed on a substrate surface decrease, it becomes increasingly important to control film properties, including film thickness and resistivity. Moreover, it may be desirable to independently tune film properties; e.g., to independently tune film thickness uniformity and resistivity in layers deposited using gas-phase reactors, such as epitaxial layers grown using such reactors. Accordingly improved gas distribution systems, reactor systems including an improved gas distribution system, and methods of using the gas distribution and reactor systems are desired.

SUMMARY OF THE DISCLOSURE

Various embodiments of the present disclosure relate to gas distribution systems, gas-phase reactor systems including a gas distribution systems, and to methods of using the gas distribution and reactor systems. While the ways in which various embodiments of the present disclosure address drawbacks of prior gas distribution systems and reactor systems are discussed in more detail below, in general, various embodiments of the disclosure provide gas distribution systems that include multiple ports, wherein a flow rate to one or more of the ports can be independently controlled. Various ports can be coupled to different gas sources to allow fine tuning of reactants provided to a substrate surface. In addition, exemplary gas distribution systems allow for independent tuning of film properties, such as film thickness, film thickness uniformity, and film resistivity.

In accordance with exemplary embodiments of the disclosure, a gas distribution system includes a flange that includes one or more first gas expansion ports formed within the flange, one or more second gas expansion ports formed within the flange, one or more first gas channels formed within the flange, wherein each of the one or more first gas channels terminate at one of the one or more of the first gas expansion ports, and one or more second gas channels formed within the flange, wherein the one or more second gas channels terminate at one or more of the second gas expansion ports. Exemplary flanges can also include one or more first conduits, wherein each first conduit is in fluid communication between a first expansion port and a reaction chamber and one or more second conduits, wherein each second conduit is in fluid communication between a second expansion port and the reaction chamber. In accordance with various aspects of these embodiments, the one or more first gas channels are fluidly coupled to a precursor source, such as a precursor source selected from the group consisting of trichlorosilane, dichlorosilane, silane, disilane, trisilane, and other semiconductor layer precursor sources. In accordance with further aspects, one or more second gas channels are coupled to a dopant source, such as a source comprising As, P, C, Ge, and B, with or without a carrier gas, such as hydrogen, nitrogen, argon, or the like. Both the precursor source and the dopant source can include suitable dopants, such as, P, C, Ge, and B. In accordance with some exemplary aspects, one or more first gas expansion ports and one or more second gas expansion ports are adjacent each other—e.g., in a front-to-back configuration relative to gas flow in a reaction chamber, to facilitate localized mixing of the first gas and the second gas. To allow fine tuning of various film or reactant properties, the gas distribution system can include an independent control valve fluidly coupled to each of the one or more first gas channels and/or to one or more of the second gas channels. This can allow independent control of gas to one or more of the first gas expansion ports and the second gas expansion ports and the respective conduits. Further, in accordance with exemplary aspects of these embodiments, two or more of the first gas channels and/or the second gas channels are coupled together upstream of the flange—e.g., between a respective gas source and a valve coupled to an expansion port. Various gas distribution systems described herein allow independent tuning of film properties across a surface of a substrate—e.g., properties near an edge of the substrate can be tuned independently from film properties away from the edge of the substrate.

In accordance with additional exemplary embodiments of the disclosure, a gas-phase reactor system includes a gas distribution system as described herein, an exhaust source coupled to the reaction chamber, a first gas source fluidly coupled to the one or more first gas channels, and a second gas source fluidly coupled to the one or more second gas channels.

In accordance with yet additional exemplary embodiments of the disclosure, a method of providing gas-phase reactants to a surface of a substrate includes the steps of providing a gas-phase reactor system, providing a gas distribution system as described herein, providing a substrate within the reaction chamber, and exposing the substrate to a first gas from the first gas source and a second gas from the second gas source. Exemplary methods can further include manipulating one or more control valves coupled to the one or more first gas channels and/or manipulating one or more control valves coupled to the one or more second gas channels. Exemplary methods can also include a step of providing an asymmetric setting of one or more of a first gas from the first gas source and a second gas from the second gas source—to, e.g., tune (e.g., independently) film properties, such as film thickness, film thickness uniformity, and film resistivity across a surface of a substrate, including an edge region of the substrate.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of exemplary embodiments of the present disclosure can be derived by referring to the detailed description and claims when considered in connection with the following illustrative figures.

FIG. 1 illustrates a cut-away view of a portion of a reactor system in accordance with exemplary embodiments of the present disclosure.

FIG. 2 illustrates a gas distribution system in accordance with exemplary embodiments of the disclosure.

FIG. 3 illustrates a portion of a gas distribution system in accordance with exemplary embodiments of the disclosure.

FIGS. 4(a)-4(f) illustrate a portion of a gas distribution system in accordance with further exemplary embodiments of the disclosure.

It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve the understanding of illustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE DISCLOSURE

The description of exemplary embodiments provided below is merely exemplary and is intended for purposes of illustration only; the following description is not intended to limit the scope of the disclosure or the claims. Moreover, recitation of multiple embodiments having stated features is not intended to exclude other embodiments having additional features or other embodiments incorporating different combinations of the stated features.

The present disclosure generally relates to gas distribution systems, to reactor systems including a gas distribution system, and to methods of using the gas distribution systems and reactor systems. Gas distribution systems and reactor systems including a gas distribution system as described herein can be used to process substrates, such as semiconductor wafers, in gas-phase reactors. By way of examples, the systems described herein can be used to form or grow epitaxial layers (e.g., doped semiconductor layers) on a surface of a substrate. As used herein, a “substrate” refers to any material having a surface onto which material can be deposited. A substrate may include a bulk material such as silicon (e.g., single crystal silicon) or may include one or more layers overlying the bulk material. Further, the substrate may include various topologies, such as trenches, vias, lines, and the like formed within or on at least a portion of a layer of the substrate.

As set forth in more detail below, use of exemplary gas distribution systems as described herein is advantageous, because it allows independent control of gas selection and flow rate at various locations within a reaction chamber. The independent control of gasses and flow rates can, in turn, allow independent tuning of film properties of films that are formed using a reactor system including the gas distribution system. For example, an exemplary gas distribution system can be used to independently tune resistivity and film thickness (or thickness uniformity) of, for example, epitaxially formed layers on a substrate. Additionally or alternatively, exemplary gas distribution systems can be used to compensate for gas flow variations, depletion rate variations, auto doping, or combinations thereof that otherwise occur within a reaction chamber of a reactor system. For example, the independent control of various gasses can be used to compensate for edge effects and/or a rotating substrate, that might otherwise cause nonuniformity in one or more film properties.

FIG. 1 illustrates a cut-away side view of an exemplary reactor system 100. Reactor system 100 includes an optional substrate handling system 102, a reaction chamber 104, a gas distribution system 106, and optionally a wall 108 disposed between reaction chamber 104 and substrate handling system 102. System 100 can also include a first gas source 302, a second gas source 306, and an exhaust source 110. During operation of reactor system 100, substrates (not illustrated) are transferred from, e.g., substrate handling system 102 to reaction chamber 104. Once substrate(s) are transferred to reaction chamber 104, one or more gasses, such as precursors, dopants, carrier gasses, and/or purge gasses are introduced into reaction chamber 104 via gas distribution system 106. Reactor system 100 can include any suitable reaction chamber 104, such as a horizontal flow, cold wall epitaxial reactor available as a system from ASM.

Referring now to FIGS. 2 and 3, gas distribution system 106 is illustrated in greater detail. Gas distribution system 106 includes a flange 202, which is described in more detail below in connection with FIGS. 4(a)-4(f). In the illustrated example, one or more (e.g., a plurality) of first gas lines 304 of gas distribution system 106 are coupled to first gas source 302 and second gas source 306 is coupled to one or more (e.g., a plurality) of second gas lines 308. Each of the first gas lines 304 and the second gas lines 308 can be coupled to a valve 310-328 to allow independent control of a flow (e.g., a flow rate) of respective gasses to channels formed within flange 202. Valves 310-328 can include any suitable automatic or manual valve that can control a flow rate of gas to a respective channel formed within flange 202. Although illustrated with two gas sources, gas distribution systems in accordance with the present disclosure can include any suitable number of gas sources.

FIGS. 4(a)-4(f) illustrate a view of a portion of flange 202 is greater detail. Flange 202 can be formed of any suitable material, such as machined stainless steel (e.g., 316 stainless steel). For a reactor system 100 designed for processing 300 mm substrates, a height H of flange 202 can range from about 207.1 mm to about 207.7 mm, or be about 207.4 mm, a length L of flange 202 can range from about 472.9 mm to about 473.5 mm, or be about 473.2 mm, and a width W of flange 202 can range from about 31.40 mm to about 31.60 mm, or be about 31.50 mm.

FIG. 4(a) illustrates a back perspective view of a portion of flange 202. FIG. 4(b) illustrates a front perspective view of a portion flange 202, having a front plate (not illustrated in FIG. 4(b)) removed. FIG. 4(c) illustrates front plan view of a portion of flange 202, with the front plate removed. FIG. 4(d) illustrates a top plan view of a portion flange 202. And, FIGS. 4(e) and 4(f) illustrate partial cut-away views of portions of flange 202, respectively illustrating first gas and second gas channels and conduits.

Flange 202 includes one or more first gas channels 330, 334, 336, 338, 342, 344, 348 fluidly coupled to first expansion ports 402-414, illustrated in FIG. 4(b), and first gas conduits 416, one of which is illustrated in FIG. 4(e) and one or more second gas channels 332, 340, and 346 fluidly coupled to second gas expansion ports 418-422 (illustrated in FIG. 4(a)) and second gas conduits 424, one of which is illustrated in FIG. 4(f). By way of examples, flange 202 can include three or more, five or more, or seven or more first expansion channels, first expansion ports, and first gas conduits and one or more, two or more, or three or more second gas channels, second gas expansion ports, and second gas conduits. In the illustrated example, flange 202 includes seven first expansion channels, first expansion ports, and first gas conduits and three second gas channels, second gas expansion ports, and second gas conduits. Gas distribution system 106 can have the same or similar number of corresponding first gas lines and/or second gas lines 308 that are coupled to the respective channels. Use of multiple channels, expansion ports, and conduits for each source gas (e.g., first gas source 302 and second gas source 306) allows fine control and tuning from each gas source of flow rates to multiple independent locations within a reaction chamber 104. This, in turn, allows independent control of film properties across a surface of a substrate.

For an exemplary flange, diameter or similar cross sectional dimension of first gas channels and second gas channels can range from 3.7 mm to about 43 mm, or be about 4.0 mm. And a length of the first gas channels can range from about 74.9 mm to about 75.5 mm, or be about 75.2 mm, and a length of second gas channels can be about 81.7 mm to about 82.9 mm, or be about 82.3 mm. First conduits can have a curved wall, creating a minimum width W1, of about 0.46 mm to about 0.66 mm, or about 0.56 mm. Similarly, second gas conduits can have a minimum width of about 0.46 mm to about 0.66 mm, or about 0.56 mm.

Referring again to FIG. 4(a), a back surface 426 of flange 202 includes an opening 428 that extends through a thickness of flange 202, such that substrates can pass—e.g., as substrates are received by or expulsed from reaction chamber 104. Back surface 426 can also include one or more grooves 430, 432 to receive a sealing element, such as an O-ring. A first plate 434 (which can form part of wall 108) can be coupled to back surface 426 to form second gas conduits (e.g., conduit 424). Similarly, with reference to FIG. 4(b) and FIG. 4(e), a second plate 436 can be coupled to a front surface 438 of a portion of flange 202 to form first gas conduits 416.

As best illustrated in FIG. 4(f), one or more of the first gas expansion ports (e.g., expansion port 402) and one or more of the second gas expansion ports (e.g., expansion port 422) can be in a front-to-back configuration, such that one or the first and second gasses exits near a front of flange 202 and the other of the first and second gas exits near the back of flange 202. This allows mixing of the first gas and the second gas near flange 202 and away from the substrate, which can mitigate any abrupt gas mixture differences across a surface of a substrate, that might otherwise lead to non-uniformities of film properties across a surface of a substrate.

As noted above, reactor system 100 and gas distribution system 106 can be used to deposit or grow layers, such as epitaxial layers on a surface of a substrate. A method of using reactor system 100 and/or gas distribution system 104 includes steps of providing a gas-phase reactor system, such as system 100 and exposing a substrate to a first gas from the first gas source (e.g., source 302) and a second gas from the second gas source (e.g., source 302). The gas flow to each of the first gas channels, the first gas expansion ports, and the first gas conduits can be individually manipulated (e.g., using valves 310, 314, 316, 318, 322, 324, and 328); and, the gas flow to each of the second channels, the second gas expansion ports, and the second gas conduits can be manipulated (e.g., using valves 312, 320, and 326) to provide the fine tuning or manipulation of film properties of, for example, a film grown. Further, because gas distribution system 106 includes a plurality of each of the first and second channels, gas expansion ports, and gas conduits, an entry location of the respective gasses can be selected and/or manipulated. Various of the valves can be opened, closed, or have their flow rates adjusted, such that the flow rates and locations of entry of the respective gases can be manipulated. By way of examples, valves 310-328 can be adjusted to provide asymmetric flow of the first gas and/or the second gas to the reaction chamber and to a surface of a substrate. This allows for, for example, compensation of substrate movement (e.g., rotation) during processing. For example, the gas flow of the first gas and/or the second gas can be biased, such that a larger volume of gas flows with the direction of a rotating substrate. Similarly, the flow rates and locations can be adjusted to compensate for edge effect (i.e., different film properties near an edge of the substrate) that would otherwise occur, and/or for autodoping, and/or precursor depletion.

Although exemplary embodiments of the present disclosure are set forth herein, it should be appreciated that the disclosure is not so limited. For example, although the gas distribution and reactor systems are described in connection with various specific configurations, the disclosure is not necessarily limited to these examples. Various modifications, variations, and enhancements of the system and method set forth herein may be made without departing from the spirit and scope of the present disclosure.

The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems, components, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof. 

We claim:
 1. A method of providing gas-phase reactants to a surface of a substrate, the method comprising the steps of: providing a gas-phase reactor system comprising: a reaction chamber; a gas distribution system comprising: a flange; an opening within the flange to receive the substrate; a plurality of first gas expansion ports formed within the flange; a plurality of second gas expansion ports formed within the flange; a plurality of first gas channels formed within the flange, wherein each of the one or more first gas channels terminate at one of the one or more of the first gas expansion ports; and a plurality of second gas channels formed within the flange, wherein the one or more second gas channels terminate at one or more of the second gas expansion ports; an exhaust source; a plurality of first gas lines coupled to a top surface of the flange and to a first gas source comprising a first gas; a plurality of second gas lines coupled to the top surface of the flange and to a second gas source comprising a second gas; a first gas source fluidly coupled to the plurality of first gas channels; a second gas source fluidly coupled to the plurality of second gas channels; a plurality of first gas valves coupled to the plurality of first gas lines and the plurality of first gas channels; and a plurality of second gas valves coupled to the plurality of second gas lines and the plurality of second gas channels, wherein a flowrate of the first gas to each of the first gas expansion ports is independently adjusted using one of the plurality of first gas valves prior to the first gas entering the flange, wherein a flowrate of the second gas to each of the second gas expansion ports is independently adjusted using one of the plurality of second gas valves prior to the second gas entering the flange, wherein the first gas and the second gas are not the same gas, and wherein the first gas and the second gas mix in the reaction chamber; providing a substrate within the reaction chamber; and exposing the substrate to a first gas from the first gas source and a second gas from the second gas source.
 2. The method of providing gas-phase reactants to a surface of a substrate of claim 1, further comprising the steps of: manipulating one or more control valves coupled to the one or more first gas channels; and manipulating one or more control valves coupled to the one or more second gas channels.
 3. The method of providing gas-phase reactants to a surface of a substrate of claim 1, further comprising the step of providing an asymmetric setting of one or more of a first gas from the first gas source and a second gas from the second gas source.
 4. A method of providing gas-phase reactants to a surface of a substrate, the method comprising the steps of: providing a gas-phase reactor system comprising: a reaction chamber; a gas distribution system comprising: a flange; an opening within the flange to receive a substrate; a plurality of first gas expansion ports formed within the flange; a plurality of second gas expansion ports formed within the flange; a plurality of first gas channels formed within the flange, wherein each of the plurality of first gas channels terminates at one of the first gas expansion ports; a plurality of second gas channels formed within the flange, wherein each of the plurality of second gas channels terminates at one of the second gas expansion ports; a plurality of first gas lines coupled to the one or more first gas channels and to a first gas source comprising a first gas; a plurality of first gas valves coupled to the plurality of first gas lines and the and the one or more first gas channels; a plurality of second gas lines coupled to the one or more second gas channels and to a second gas source comprising a second gas; a plurality of second gas valves coupled to the plurality of second gas lines and the and the one or more second gas channels; a plurality of first conduits; and a plurality of second conduits, wherein each first conduit is in fluid communication between one of the first gas expansion ports and a reaction chamber, wherein each second conduit is in fluid communication between one of the second gas expansion ports and the reaction chamber, wherein a flowrate of the first gas to each of the first gas expansion ports is independently adjusted using one of the plurality of first gas valves prior to the first gas entering the flange, wherein a flowrate of the second gas to each of the second gas expansion ports is independently adjusted using one of the plurality of second gas valves prior to the second gas entering the flange, wherein a plurality of first gas lines and a plurality of second gas lines are coupled to a top surface of the flange, wherein the first gas and the second gas are not the same gas, and wherein the first gas and second gas mix within the reaction chamber; providing a substrate within the reaction chamber; and exposing the substrate to a first gas from the first gas source and a second gas from the second gas source.
 5. The method of providing gas-phase reactants to a surface of a substrate of claim 4, further comprising the steps of: manipulating one or more control valves coupled to the one or more first gas channels; and manipulating one or more control valves coupled to the one or more second gas channels.
 6. The method of providing gas-phase reactants to a surface of a substrate of claim 4, further comprising the step of providing an asymmetric setting of one or more of a first gas from the first gas source and a second gas from the second gas source. 